Field of the Invention
The invention relates to a device for transmitting electrical current and/or signals in a motor vehicle, wherein the device has a wind up spring cassette consisting of a stator and a rotor, and at least one fixing element through which the relative positions of the stator and the rotor of the wind up spring cassette are fixed in the wind up spring cassette in the steering wheel of the motor vehicle. In the wind up spring cassette, at least one line extending in windings is arranged which is connected with one end to the stator and with the other end to the rotor.
Description of Related Art
Wind up springs are preferably used today in motor vehicles for transmitting electrical or optical signals, for example, for triggering the air bag in the steering wheel, between stationary and moveable motor vehicle parts. The line may comprise electrical and/or optical lines. Wind up springs ensure a secure and permanent electrical and/or optical connection. Wind up springs are called lines which are wound within the cassette either spirally in concentric windings for winding a core in the cassette, or are in a loop guided around a core in the cassette (the latter also being called short strip winding spring or U-turn winding spring). With its two ends, the line connects a structural component (the rotor) rotatable with the steering wheel to a structural component (the stator) fixed to the motor vehicle optically and/or electrically to each other. Wind up springs permit a relative rotational movement of the stator and of the rotor without impairing the secure electrical and/or optical connection between vehicle components which are fixed relative to the vehicle and steering wheel. The line may be, for example, a flexible flat band line (FBL), i.e. conducting webs which are embedded in the insulating material at a distance from each other. The rotor and the stator together form a housing which receives the line, which is also called the wind up spring cassette.
For mounting the wind up spring cassette in the steering wheel of a motor vehicle, it is important that the two ends of the FBL or of another line assume a certain position relative to each other. This ensures that the predetermined rotations of the rotor can be carried out in both directions of the steering wheel without the line tearing from the cassette.
DE 42 16 526 A1 describes an electrical line extending in windings accommodated in a circular cassette, wherein the cassette is composed of a rotor rotatable about the axis of the cassette, and a stator. In order to hold the two components in a certain position during mounting in the steering wheel of a motor vehicle, an outwardly projecting attachment is provided on the rotor for receiving a screw and a spring adjustable by means of the screw. In the mounted position of the cassette, a spring is pressed into a recess of the stator, so that the rotor immovably rests against the stator. In the position of operation, the locking action is removed by loosening the screw.